Cabinet ReBuild for Coaxial Drivers Tannoy Red/Gold

I'm in the process of reading, scratching my head, reading some more, getting new ideas, following a tangent thought, and scratching my head more, in trying to decide what to do with a set of tannoy reds or gold monitor 12's(non rubber) and just recently a thread about goodmans 100c triaxials poped it's head up.

To start with, I have a set of monitor 12 golds in Mallorcan cabinets, always read that the cabs are too small and limit the speakers. Enter the monitor 12 reds that came to me in non-descript black painted square 190lts plywood cabinets with 4" shallow ports. Bass was very much there, but cabs are UGLY and do not have a future(already cut up for parts for new build).

I managed to find, for better or worse, a set of donor cabinets around 125lts with sides and top in solid cherry and back and bottom in particle board. Not the best starting point, but they look nice so we'll see.

The primary issue I seem to be having is how to vent, aperiodic vent ala goodmans ARU, a round port, or square port. As well as how to vent, to make the best of the two tannoy options I have, if that is even possible. I'm leaning towards some type of aperiodic vent that I can add/remove material and tune them in place, and mount this in the rear.

And more importantly how to brace the cabinet walls. My initial thought, is to use triangle shaped brackets around the sides and back and some cross trusses on the front to support the baffle. My concern is too much bracing I limit volume of the cabinet, and not enough I may have too much resonance of the wood. I do have a good supply of dynamat type material, enough to adhere to both cabs (I think) as well as some mass loading sheets (both from a VW Bus sound deadening project)

I will also need to do the cross overs.

I'm sure I will have more, and I will post photos and decisions and observations that I have along the way. I am a DIY at heart, but a horrible researcher and I tend to work from trial and error. I have done quite a bit of the remodeling in my house and would rate myself as moderately skilled carpenter.

Any thoughts, jeers, cheers or otherwise are appreciated. I've grown tire of buying stuff and need to be creative for a change. (I've cross posted this to DIY Audio as well)

Finished my bracing, major difference. I'm going to continue cabinet control with dynamat, followed by cotton or dacron batting. Dacron most likely as I'm in a basement and don't want to risk anything.

Oh and feet, found a great thread on skateboard wheels for vibration control, can't hurt. Will give it a try. Going to try and find what are called 72a (can't remember the scale name right now) either skateboard of inline skate wheels.

This may be totally meaningless, but I decided to use a spectrum analyzer on android on my cabinets after adding dynamat to the back of one of the cabinets.

Test method, knuckle raps on the back of the cabinet, one with dynamat, the other without.

I overlaid the two results, very quickly, just to see the changes.

Does this support more dynamat, or does not, or totally meaningless.

c-atle-79bay said:

This may be totally meaningless, but I decided to use a spectrum analyzer on android on my cabinets after adding dynamat to the back of one of the cabinets.

Test method, knuckle raps on the back of the cabinet, one with dynamat, the other without.

I overlaid the two results, very quickly, just to see the changes.

Does this support more dynamat, or does not, or totally meaningless.

Click to expand...

I'm confused - what do the numbers in the horizontal and vertical grids mean? I would assume frequency and decibels respectively, but I am still confused with that criteria. At a glance, it doesn't seem to make much difference.

Red is with dynamat.

My assumption of the graph was frequency in hz from 0 to 22,050 and level of that frequency in db.

My assumption was that I have lowered the peak db of the cabinet (back wall in this case) from 2,000hz to 10,000 hz, and made the box more neutral/flat/deader. Again this is my fully untrained assumption.

Those boxes look the ~right size.. Good.
IF you need an even better alternate?? Buy some Torch-on SBS membrane (Construction supplies business) Surprisingly Cheap and 1/4" thick.
Needs a heat gun to apply it though.
Seriously superior to the relabeled Ice 'n water shield sold as Dynamat for a fraction of the price.
A few glued on bits of 1x2 lumber would easily outperform the stick on tar though.. your choice
V good info here if you've not seen it before (suggest you read it ALL
http://www.44bx.com/tannoy/

Thanks for the info on the SBS membrane. Have not read all the tannoy pages, just what seems to apply, unfortunate, have to target my reading.

If these cabs work nicely, will think about a better larger build of one of the tannoy based designs, not lots of time into them so far, a few min hear and there. So not much to loose.